PhD Project
Zinc isotope fractionation in
sediment-hosted Zn-Pb deposits
Dr. Jamie Wilkinson & Dr Dominik Weiss
AIM To determine the extent and controls of zinc isotope variation in sediment-hosted Zn-Pb ore deposits
as a potential tool for mineral exploration.
BACKGROUND Our knowledge of the controls of zinc isotope variation in hydrothermal systems is limited
to just a few studies of ore deposits (Mason et al., 2003; Wilkinson et al., 2005; Kelley et al., in revision) and
modern submarine systems (John et al., 2008). The data that exist show that almost the entire terrestrial
range of zinc isotope compositions is observed
within such systems implicating hydrothermal
processes as a major control of isotopic
fractionation. The generation of systematic
patterns attributed to Rayleigh fractionation
processes during sphalerite precipitation provides
a potential useful tool in the exploration for
mineral resources.
OBJECTIVES The principal objective of the study
Aerial view of the Red Dog mine, Brooks Range, Alaska. New data
have shown that there are important variations in Zn isotope
compositions in this district that could help to locate further Zn-Pb
resources.
is to determine the Zn isotopic variability of
sphalerite and trace Zn in altered rocks in
sediment-hosted ore systems. These results will be
used to test models of isotopic fractionation and
evaluate the potential for fingerprinting ore
signatures and targeting mineral exploration.
METHODS Logging and sampling of drillcore and underground mine exposures will be carried out in the
Irish Zn-Pb orefield and potentially other districts. The study will utilise wet chemistry laboratory facilities
located in the Department. Chemical analyses will be carried out using ICP-AES and ICP-MS instruments, and
isotope measurements will be made using the Department’s Nu Plasma multi-collector ICP-MS located in the
Royal School of Mines Building. Experiments will be carried out to refine existing analytical methods and
improve the accuracy and precision of isotope data. Sample characterization will be carried out using optical
microscopy and scanning electron microscopy.
WIDER IMPLICATIONS The research will help advance the currently limited understanding of transition
metal fractionation in hydrothermal systems and the development of a new tool for mineral exploration.
STUDENT PROFILE We are looking for a well-qualified and highly motivated Earth Sciences/Geology
graduate with a strong interest in geochemistry and hydrothermal mineralization. Experience of geochemical
analytical methods would be an advantage.
TRAINING The successful student will join a vibrant research group in geochemistry at Imperial College.
The student will receive training in field sampling, laboratory best practice, sample preparation methods,
inductively-coupled plasma atomic emission and mass spectrometry and data reduction methods. Training
also will be given in characterization techniques including reflected and transmitted light petrography,
scanning electron microscopy and PIXE analysis. Courses in isotope geochemistry, fluid geochemistry and
mineralising processes and transferable skills will be available.
FURTHER INFORMATION If you are interested in the project and would like to have further details
please contact Jamie Wilkinson at j.wilkinson@imperial.ac.uk
http://www3.imperial.ac.uk/people/j.wilkinson
http://www3.imperial.ac.uk/earthscienceandengineering/research/lode
REFERENCES
John, S.G., Rouxel, O.J., Craddock, P.R., Engwall, A.M., and Boyle, E.A., 2008, Zinc stable isotopes in seafloor
hydrothermal vent fluids and chimneys: Earth and Planetary Science Letters, v. 269, p. 17-28.
Kelley, K.D., Wilkinson, J.J., Chapman, J.B., Crowther, H.L., and Weiss, D.J., in revision, Zinc isotopes in
sphalerite from base metal deposits in the Red Dog district, Northern Alaska: Economic Geology.
Mason, T.F.D., Weiss, D.J., Chapman, J.B., Wilkinson, J.J., Tessalina, S.G., Spiro, B., Horstwood, M.S.A., Spratt, J.,
and Coles, B.J., 2005, Zn and Cu isotopic variability in the Alexandrinka volcanic-hosted massive sulfide
(VHMS) ore deposit, Urals, Russia: Chemical Geology, v. 221, p. 170-187.
Wilkinson, J.J., Weiss, D.J., Mason, T.F.D., and Coles, B.J., 2005, Zinc isotope variation in hydrothermal systems:
Preliminary evidence from the Irish Midlands ore field: Economic Geology, v. 100, p. 583-590.